A(1) Field of the invention.
The invention relates to an arrangement for checking the synchronization of a receiver for data signals having a spectrum comprising two sidebands located one on each side of a symbol frequency.
Arrangements of the above type are called monitoring devices. Synchronizing the receiver is usually effected by a clock signal device which derives a synchronous clock signal from the data signal on the basis of clock information present in the data signal itself. By means of a non-linear processing of the received data signal, a strong signal component having a frequency of twice the symbol frequency can be obtained. The clock signal which is required for signal regeneration, must be derived from this signal component by means of frequency division, which causes an ambiquity in the phase of the clock signal. A monitoring device serves to determine the correct phase of the clock signal.
A(2) Description of the prior Art.
In a known monitoring circuit for bi-phase modulation (Manchester code) in accordance with U.S. Pat. No. 3,403,377 the monitoring criterion is derived from the transitions in the received data signal. This criterion is sensitive to signal distortion due to the transmission path.